Jupiter turns into orange halo

Jemmo (Adrian) · #1 13-01-2015, 11:15 AM

Hey all last night I was trying to see Jupiter through my 3" Newtonian I now it's not a great scope to see Jupiter with but I couldnt really focus on it I kept getting and orange ring or halo. What causes this

ralph1 · #2 13-01-2015, 12:00 PM

Hi Adrian. That sounds like the telescope isn't focussed properly. Turn the focus knob(one of the two knobs beneath the eyepeice) until jupiter(or any other object) appears smallest and sharpest. On jupiter you should see a small disk with up to four dots in a line beside it. Those are jupiters galilean moons. Depending on the magnification you might also see two or more stripes on jupiter itself. Those are its cloud bands.

raymo · #3 13-01-2015, 01:36 PM

I don't mean to be patronising,[not knowing your knowledge level],
but are you sure you were looking at Jupiter? It doesn't rise until
around midnight, and would not be high enough in the sky to be reasonably well viewed until around 1.30-2.00am. I've never heard of anything resembling a ring or halo around it. Maybe it could happen with a child's toy scope with a plastic lens. Even a budget level 3" Newt
should give a nice sharp image of Jupiter.
raymo

ralph1 · #4 13-01-2015, 03:55 PM

I often see Halos around the moon from haze. Why couldn't a similar thing happen to jupiter? if you go outside around midnight jupiter is the brightest object in the sky, about one handwidth up from the horizon in the northeast.

Jemmo (Adrian) · #5 13-01-2015, 04:41 PM

Jupiter is visible at 11pm in my area and yes I'm 100% it was Jupiter. I don't mean it has a halo around it I get like a black dot in the center as if it's doing circles very fast like a donut shape. It was quite a windy night as well

Larryp (Laurie) · #6 13-01-2015, 04:47 PM

Sounds like you are not achieving focus.

OzStarGazer · #7 13-01-2015, 04:49 PM

Quote:

Originally Posted by Jemmo

I get like a black dot in the center as if it's doing circles very fast like a donut shape. It was quite a windy night as well

I think that a doughnut shape indicates that your scope is out of focus. Is the image tiny or big? I have noticed a doughnut shape when my scope was out of focus; specifically the image was too big.

Jemmo (Adrian) · #8 13-01-2015, 05:25 PM

Ok thanks guys I don't think my scope will get a great shot of Jupiter think it's a bit small I got the donut to go away but I couldn't get a great shot just an orange circle couldn't make out moons or lines etc

ralph1 · #9 13-01-2015, 05:33 PM

Any scope should show jupiter well - it shows a clear disk and moons in 10X50 binoculars.

OzStarGazer · #10 13-01-2015, 05:40 PM

My refractor is just a bit bigger (90mm) and I can see it very clearly, including the moons and the bands, even with my 25mm eyepiece when the weather conditions are not too bad. But yes, it is small.

raymo · #11 13-01-2015, 06:18 PM

The black dot you are seeing in the middle of Jupiter will almost certainly
be the scope's secondary mirror, which means that the focus is well off.
If you focus so that stars are as small as you can get them you won't be far off with Jupiter. As Ralph said, even 50mm binos will show it clearly, so either you are not focussing properly, or something is drastically
wrong with your scope.
raymo

Jemmo (Adrian) · #12 13-01-2015, 06:36 PM

Was clear night but very windy. I think maybe I was trying to zoom too much I had the 1.5x erecting eye peice on then worked up to 9mm lense. Maybe I should ditch the 1.5 piece and use a lower lense than the 9mm I have a 12.5 and 25mm lense too. I reckon I was pushing the scope past its limits

barx1963 (Malcolm) · #13 13-01-2015, 06:49 PM

Adrian
Always start with your lowest power and build up from there to find the best image.
Also waiting until it is reasonably high in the sky will help.

The black dot you were seeing is actually the secondary mirror image. If you find a reasonably bright star in your scope and defocus the same black spot will appear, nothing wrong with the scope, just another normal property of newtonians.
One other thing, your mentioned using a 1.5x erecting eyepiece. 2 comments on these, they tend to be very cheap accessories, the one I had was very poorly made, and are usually supplied so a scope can be used for terrestrial targets, as a result are designed to be used with low power and not necessarily focussing at infinity.

Malcolm

barx1963 (Malcolm) · #14 13-01-2015, 06:51 PM

I realise your scope is a 75/700 now, so a 9mm with a 1.5x erecting EP will give 117x, which for 3" is pushing it, not impossible but would need good seeing and for Jupiter to be highish.

Jemmo (Adrian) · #15 13-01-2015, 08:17 PM

I'll try again with no 1.5x piece when it's clear. I'm actually picking up a 10" dobsonian on sat. I don't get lenses I only have the ones that came with the newt. Which wasn't very expensive. What are a good set of lenses that aren't real expensive. As I'm low on cash after buying the dobsonian. The cheap lenses will do for now but need to upgrade. Also are the filters good to get. I have a moon one no colors though

barx1963 (Malcolm) · #16 13-01-2015, 10:13 PM

Adrian
Are you able to post a picture of the eyepieces ( that is the correct term, lense refers to an element within the eyepiece) that you have? Or any descriptive text that is on them. Just gives us an idea what you have so then can suggest a suitable upgrade.

Malcolm

creeksky (Pete) · #17 13-01-2015, 10:24 PM

Quote:

Originally Posted by barx1963

I realise your scope is a 75/700 now, so a 9mm with a 1.5x erecting EP will give 117x, which for 3" is pushing it, not impossible but would need good seeing and for Jupiter to be highish.

Shouldn't he see Jupiter and moons even as a large white disc?
Not questioning your expertise,but with a 20 mm refractor 40 years ago I could make it out?

barx1963 (Malcolm) · #18 13-01-2015, 10:56 PM

Quote:

Originally Posted by creeksky

Shouldn't he see Jupiter and moons even as a large white disc?
Not questioning your expertise,but with a 20 mm refractor 40 years ago I could make it out?

The question is whether the 1.5x erecting eyepiece and the 9mm EP are able to achieve focus, they may not be designed to do so. He shoudl be able to see the disc and the moons even with the 25mm EP. From experience best procedure with any object that required power is start at low power and work up from there.

Malcolm

OzStarGazer · #19 14-01-2015, 06:08 AM

Quote:

Originally Posted by creeksky

Shouldn't he see Jupiter and moons even as a large white disc?
Not questioning your expertise,but with a 20 mm refractor 40 years ago I could make it out?

I think Malcolm meant that the 117x magnification would be too much for the OP's scope. Lower magnifications would be fine to see it (even if small).

Jemmo (Adrian) · #20 14-01-2015, 07:06 AM

I can't get any photos of the eye peices at the moment. The best info I can give is that the telescope I got was a gift it's one of those generic brands which I tihk there may be like 5 different brand names. Mine is a national geographic 75/700 Newtonian I think it's around the $200 mark so yeah don't think the eye pieces will be much chop